Introduction

Essentials of Diagnosis

• Red streak extending from an infected area toward enlarged, tender regional lymph nodes.
• Chills, fever, and malaise may be present.

General Considerations

Lymphangitis and lymphadenitis frequently accompany a streptococcal or staphylococcal infection in the distal arm or leg. The inciting wound may be a superficial scratch with cellulitis, an insect bite, or an established abscess. A prominent red streak extending toward tender, enlarged regional lymph nodes is diagnostic. Systemic manifestations include fever, chills, tachycardia, and malaise. If untreated, the infection can progress rapidly, often in a matter of hours.

Clinical Findings

A. Symptoms and Signs
Throbbing pain at the site of the inciting wound is usually present. Malaise, anorexia, sweating, chills, and fever of 37.8-40°C develop rapidly. The red streak may be faint initially and easily missed, especially in dark-skinned patients. The involved regional lymph nodes may be significantly enlarged and tender.

B. Laboratory Findings

Leukocytosis with a left shift is usually present. Blood cultures are often positive for staphylococcal or streptococcal species. Wound cultures may be helpful in treatment of the more severe or refractory infections but are often difficult to interpret because of skin contaminants.

Differential Diagnosis
Superficial thrombophlebitis is distinguished from lymphangitis by the pattern of erythema (localized to an indurated thrombosed vein) and the lack of lymphadenitis. Cat-scratch disease caused by Bartonella henselae typically presents with enlarged but nontender lymph nodes. Lymphangitis must also be differentiated from cellulitis and from severe soft tissue infections such as acute streptococcal hemolytic gangrene and necrotizing fasciitis requiring emergent debridement. These infections are nonlinear and are characterized by induration and subcutaneous crepitus.

Treatment
The extremity is elevated, and warm compresses are applied to the involved area. Analgesics and intravenous antibiotics (penicillin G, 4 million units every 6 hours, or cefazolin, 1 g every 8 hours) should be instituted immediately. Examination of the wound will determine the need for debridement or incision and drainage of an abscess.

Prognosis
Early institution of appropriate antibiotic therapy and wound care will usually control the infection in 48-72 hours. Delayed or inadequate therapy can result in rapidly progressive infection, septicemia, and death.